[Python-checkins] Fix Tools/gdb/libpython.py
Miss Islington (bot)
webhook-mailer at python.org
Tue Sep 11 13:35:12 EDT 2018
https://github.com/python/cpython/commit/ed74a258aab2d5ca56a311acffdc7a46ca8ce2a1
commit: ed74a258aab2d5ca56a311acffdc7a46ca8ce2a1
branch: 3.6
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2018-09-11T10:35:08-07:00
summary:
Fix Tools/gdb/libpython.py
Backport https://github.com/python/cpython/commit/11659d00b9185c8f02ea6b642fa475a80e21f1a9
into this change instead of leaving it a separate followup change.
files:
A Misc/NEWS.d/next/Core and Builtins/2018-04-19-08-30-07.bpo-33312.mDe2iL.rst
M Objects/dict-common.h
M Objects/dictobject.c
M Tools/gdb/libpython.py
diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-04-19-08-30-07.bpo-33312.mDe2iL.rst b/Misc/NEWS.d/next/Core and Builtins/2018-04-19-08-30-07.bpo-33312.mDe2iL.rst
new file mode 100644
index 000000000000..40b51b902c9f
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2018-04-19-08-30-07.bpo-33312.mDe2iL.rst
@@ -0,0 +1,3 @@
+Fixed clang ubsan (undefined behavior sanitizer) warnings in dictobject.c by
+adjusting how the internal struct _dictkeysobject shared keys structure is
+declared.
diff --git a/Objects/dict-common.h b/Objects/dict-common.h
index ce9edabd8959..d3ae07bfd3f4 100644
--- a/Objects/dict-common.h
+++ b/Objects/dict-common.h
@@ -59,15 +59,8 @@ struct _dictkeysobject {
- 4 bytes if dk_size <= 0xffffffff (int32_t*)
- 8 bytes otherwise (int64_t*)
- Dynamically sized, 8 is minimum. */
- union {
- int8_t as_1[8];
- int16_t as_2[4];
- int32_t as_4[2];
-#if SIZEOF_VOID_P > 4
- int64_t as_8[1];
-#endif
- } dk_indices;
+ Dynamically sized, SIZEOF_VOID_P is minimum. */
+ char dk_indices[]; /* char is required to avoid strict aliasing. */
/* "PyDictKeyEntry dk_entries[dk_usable];" array follows:
see the DK_ENTRIES() macro */
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index ddd05826ea5f..0768d1154542 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -300,7 +300,7 @@ PyDict_Fini(void)
2 : sizeof(int32_t))
#endif
#define DK_ENTRIES(dk) \
- ((PyDictKeyEntry*)(&(dk)->dk_indices.as_1[DK_SIZE(dk) * DK_IXSIZE(dk)]))
+ ((PyDictKeyEntry*)(&((int8_t*)((dk)->dk_indices))[DK_SIZE(dk) * DK_IXSIZE(dk)]))
#define DK_DEBUG_INCREF _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA
#define DK_DEBUG_DECREF _Py_DEC_REFTOTAL _Py_REF_DEBUG_COMMA
@@ -318,21 +318,21 @@ dk_get_index(PyDictKeysObject *keys, Py_ssize_t i)
Py_ssize_t ix;
if (s <= 0xff) {
- int8_t *indices = keys->dk_indices.as_1;
+ int8_t *indices = (int8_t*)(keys->dk_indices);
ix = indices[i];
}
else if (s <= 0xffff) {
- int16_t *indices = keys->dk_indices.as_2;
+ int16_t *indices = (int16_t*)(keys->dk_indices);
ix = indices[i];
}
#if SIZEOF_VOID_P > 4
else if (s > 0xffffffff) {
- int64_t *indices = keys->dk_indices.as_8;
+ int64_t *indices = (int64_t*)(keys->dk_indices);
ix = indices[i];
}
#endif
else {
- int32_t *indices = keys->dk_indices.as_4;
+ int32_t *indices = (int32_t*)(keys->dk_indices);
ix = indices[i];
}
assert(ix >= DKIX_DUMMY);
@@ -348,23 +348,23 @@ dk_set_index(PyDictKeysObject *keys, Py_ssize_t i, Py_ssize_t ix)
assert(ix >= DKIX_DUMMY);
if (s <= 0xff) {
- int8_t *indices = keys->dk_indices.as_1;
+ int8_t *indices = (int8_t*)(keys->dk_indices);
assert(ix <= 0x7f);
indices[i] = (char)ix;
}
else if (s <= 0xffff) {
- int16_t *indices = keys->dk_indices.as_2;
+ int16_t *indices = (int16_t*)(keys->dk_indices);
assert(ix <= 0x7fff);
indices[i] = (int16_t)ix;
}
#if SIZEOF_VOID_P > 4
else if (s > 0xffffffff) {
- int64_t *indices = keys->dk_indices.as_8;
+ int64_t *indices = (int64_t*)(keys->dk_indices);
indices[i] = ix;
}
#endif
else {
- int32_t *indices = keys->dk_indices.as_4;
+ int32_t *indices = (int32_t*)(keys->dk_indices);
assert(ix <= 0x7fffffff);
indices[i] = (int32_t)ix;
}
@@ -424,8 +424,8 @@ static PyDictKeysObject empty_keys_struct = {
lookdict_split, /* dk_lookup */
0, /* dk_usable (immutable) */
0, /* dk_nentries */
- .dk_indices = { .as_1 = {DKIX_EMPTY, DKIX_EMPTY, DKIX_EMPTY, DKIX_EMPTY,
- DKIX_EMPTY, DKIX_EMPTY, DKIX_EMPTY, DKIX_EMPTY}},
+ {DKIX_EMPTY, DKIX_EMPTY, DKIX_EMPTY, DKIX_EMPTY,
+ DKIX_EMPTY, DKIX_EMPTY, DKIX_EMPTY, DKIX_EMPTY}, /* dk_indices */
};
static PyObject *empty_values[1] = { NULL };
@@ -533,7 +533,6 @@ static PyDictKeysObject *new_keys_object(Py_ssize_t size)
}
else {
dk = PyObject_MALLOC(sizeof(PyDictKeysObject)
- - Py_MEMBER_SIZE(PyDictKeysObject, dk_indices)
+ es * size
+ sizeof(PyDictKeyEntry) * usable);
if (dk == NULL) {
@@ -546,7 +545,7 @@ static PyDictKeysObject *new_keys_object(Py_ssize_t size)
dk->dk_usable = usable;
dk->dk_lookup = lookdict_unicode_nodummy;
dk->dk_nentries = 0;
- memset(&dk->dk_indices.as_1[0], 0xff, es * size);
+ memset(&dk->dk_indices[0], 0xff, es * size);
memset(DK_ENTRIES(dk), 0, sizeof(PyDictKeyEntry) * usable);
return dk;
}
@@ -3086,7 +3085,6 @@ _PyDict_SizeOf(PyDictObject *mp)
in the type object. */
if (mp->ma_keys->dk_refcnt == 1)
res += (sizeof(PyDictKeysObject)
- - Py_MEMBER_SIZE(PyDictKeysObject, dk_indices)
+ DK_IXSIZE(mp->ma_keys) * size
+ sizeof(PyDictKeyEntry) * usable);
return res;
@@ -3096,7 +3094,6 @@ Py_ssize_t
_PyDict_KeysSize(PyDictKeysObject *keys)
{
return (sizeof(PyDictKeysObject)
- - Py_MEMBER_SIZE(PyDictKeysObject, dk_indices)
+ DK_IXSIZE(keys) * DK_SIZE(keys)
+ USABLE_FRACTION(DK_SIZE(keys)) * sizeof(PyDictKeyEntry));
}
diff --git a/Tools/gdb/libpython.py b/Tools/gdb/libpython.py
index 6d7a94247bc3..6d3d52f397d4 100755
--- a/Tools/gdb/libpython.py
+++ b/Tools/gdb/libpython.py
@@ -736,7 +736,7 @@ def _get_entries(self, keys):
else:
offset = 8 * dk_size
- ent_addr = keys['dk_indices']['as_1'].address
+ ent_addr = keys['dk_indices'].address
ent_addr = ent_addr.cast(_type_unsigned_char_ptr()) + offset
ent_ptr_t = gdb.lookup_type('PyDictKeyEntry').pointer()
ent_addr = ent_addr.cast(ent_ptr_t)
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